It is well understood that the cross-linking of polymers improves the physical properties such as memory, heat resistance, resistance to chemicals, stiffness, etc. of the polymer. Current methods used for cross-linking polymers include the use of: radiation; free radical generating agents as described by U.S. Pat. No. 4,389,514; free radical generating agent, a silane and condensation catalyst as described by U.S. Pat. Nos. 3,646,155, 4,117,195 and 4,444,948; and silyl modified polymer reacted with an organo titanate (U.S. Pat. No. 4,526,930) or a phosphorus or antimony compound (U.S. Pat. No. 4,574,133) and optionally, a silanol condensation catalyst. U.S. Pat. No. 4,487,883 describes a process wherein a polymer having nitrogen-hydrogen bonding is cross-linked by reaction with a hydrolyzable titanate, zirconate, vanadate or germanate. The cross-linked polymer reverts to noncross-linked after exposure to liquid water. Japanese patent application No. 29530, filed Mar. 17, 1976 (Public Disclosure No. 111933-1977) describes the cross-linking of organic polymers by use of a hydrolyzable titanium compound and a free radical generating agent.